Taliban infiltrators are quietly colonising Pakistani border areas and setting up a logistics base which is being boosted by volunteers, medical treatment, cash and food.

US warplanes roar overhead on their way to Afghanistan but they cannot touch the Taliban networkers who are successfully tapping religious, tribal and family ties, making the wild, sun-baked plains of Baluchistan province a sanctuary from the bombing.

Several times a week ambulances deposit wounded fighters at hospitals in Quetta, the province's biggest city, and in the opposite direction new recruits and former veterans, including doctors, make the six-hour car drive to Kandahar, the Taliban's spiritual stronghold in southern Afghanistan.

Daily donations collected at mosques, bazaars, homes and offices now exceed £10,000, according to Said Sanan, a Taliban officer who defected to Pakistan two weeks ago. "Baluchistan is important to the Taliban. They are soaking up the support."

In an ominous development for the allies, two US helicopters came under fire in Pakistan earlier this week as they tried to retrieve the wreckage of another helicopter which crashed during a raid.

Some analysts say Baluchistan could become a rallying point from which militants could launch a guerrilla campaign against a post-Taliban government should they be ousted from Afghanistan.

Pakistan's military ruler, General Pervez Musharraf, has discarded his country's alliance with the Taliban in favour of cosying up to Washington and the army and intelligence services appear to toe the new line.

But perhaps because popular support for Mullah Mohammad Omar's regime has never been higher there is little crackdown on Taliban visitors. In Quetta's Gulshan district there is a lane locals have christened Taliban Road.

Three white flags, an Islamic emblem, flutter over the 18ft brick walls ringing a compound at No 21-8, and several times a day the pink corrugated doors swing open for a small fleet of Hiace vans to go about their business.

Fighters fresh from surgery at nearby hospitals recuperate in the shaded courtyard before returning to jihad. Recruiters seeking volunteers among the Pakistani youth stay here, as do quartermasters who stock up on supplies. The vans melt into refugee columns at the border crossing of Chaman, 80 miles to the northwest, and surgeons in at least two hospitals are understood to operate discreetly and for free.

Pakistani security forces patrol the vast frontier but their chances of intercepting the Taliban or its material are minimal. Last week an Oxfam water engineer discovered 135 rocket-propelled grenades and five anti-tank mines in the air vent of an underground pipe.

The Taliban's popularity grows as the bombing continues. "My God, it is terrible, the Taliban's support is increasing by the day," said Maudir Bakht, a political scientist at Quetta's university. "Before the bombing they were disliked by a majority of Pakistanis but now there is a level of moral and humanitarian support which may start turning military."

Professor Bakht said Afghan refugees risked turning Baluchistan into the staging post for a new civil war in Afghanistan should a pro-western government replace an ousted Taliban. "We should not let them in," he said.

The violent street protests which convulsed the city at the beginning of the air campaign have been snuffed out by police bullets but beneath the surface Quetta is churning.

Abdul Khaliq is the richest man in Pashtoon Abad, a thriving satellite town of 200,000 Afghan refugees who fled the Russians 20 years ago. "I never supported the Taliban and nor did my neighbours but now we are totally behind them. We are collecting money and are waiting for the call to fight."